C++: Synchronize function decl/def refactoring.

When editing a function declaration or definition the code model
may realize the same changes have to be applied somewhere else. A
refactoring marker will pop up that can be clicked to perform the
changes. Alternatively, press enter to apply.

Change-Id: I2299a2ecfb6a8f87d4853fc7cfa99486f890a1d3
Reviewed-on: http://codereview.qt.nokia.com/2909


Reviewed-by: Leandro T. C. Melo <leandro.melo@nokia.com>